Tensorflow Lite c++ external delegates

I have a c++ project (cmake) and integrate Tensorflow Lite for face detection. The application works well and is running on the CPU of my SOC (with XNNPACK delegates).
As my SOC (iMX8 Plus) has a NPU, I want to use the external delegate path to include VX-delegate library.
But I get linker errors at compilation (undefined reference to ‘TfLiteExternalDelegateCreate’).

Has anyone a working example of a cmake project, to include Tensorflow Lite and tflite-vx-delegate-imx?